The present invention relates to a safety system and method for preventing any accident which may occur during operation of a robot.
At present, industrial robots can accurately simulate the motion of human hands and, hence, have acquired acceptance as excellent replacements for human laborers, particularly in the fields of automation which could never be achieved by conventional machine technology, as well as in the area of simple monotonous operations and those operations taking place under severe working conditions which operations could not be sustained by human laborers. In fact, many robots are actually used in various production lines.
Most of the industrial robots are adapted to operate in accordance with a predetermined sequence or to play back a motion in accordance with the data content of a teaching device. Once the playing back operation is started by, for example, the setting of the object to be worked (referred to as "work", hereinunder), the operation of the manipulator is successively performed until a series of steps in accordance with the taught data content is completed.
The aforementioned robots are subject to the possibility of accident as a result of contact between the movable part or tool on the robot and a person or any obstacle which may accidently come into the area of reach or movement of the robot during the playback operation or automation operation of the robot. The accident may also be caused by incorrect contact between the tool and work when the work is improperly set.
In order to avoid the possibility of such accidents, hitherto, safety measures have been taken such as the demarcation of a danger zone around the robot so as to keep persons away from the area of reach of the robot by, for example, the setting up of a fence.
These conventional safety measures, however, require additional space for the safety zone and impair the efficiency of various necessary operations such as the setting of the work, or the inspection and maintenance of the robot. In addition, these conventional measures are ineffectual in avoiding the danger when, for example, a person accidentally steps into a danger zone or when an obstacle is improperly placed in the zone.